title: Influence of the family cluster effect on psychosocial variables in families undergoing BRCA1/2 genetic testing for cancer susceptibility.
abstract: OBJECTIVE
  This study evaluated the influence of the family cluster effect on behavioral and psychological variables among individuals undergoing BRCA1/2 genetic testing for cancer susceptibility.
  
  
  METHODS
  French-Canadian women (n = 552) and men (n = 104) from 140 different families undergoing BRCA1/2 testing between years 1998 and 2004 completed a self-administered questionnaire on a wide range of behavioral and psychological variables. The impact of the family cluster effect on 29 variables was assessed using the intraclass correlation coefficient (ICC) as computed from multilevel random-effect models.
  
  
  RESULTS
  ICC values were statistically significant for 22 of the 29 variables. Overall, the mean ICC value was 0.10. The ICC values for knowledge about hereditary breast and ovarian cancer and frequency of alcohol consumption were 0.25. The ICC value for the Impact of Event Scale, which is a commonly used measure of cancer-specific distress, was 0.14.
  
  
  CONCLUSIONS
  Our results suggest that the family cluster effect influences the majority of behavioral and psychosocial variables. When studying psychosocial aspects of genetic testing for cancer susceptibility, the family cluster effect should be routinely accounted for when determining sample size and statistical methods.
authors.affiliation: Faculté de pharmacie, Université Laval, Québec City, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Lapointe
authors.forename: Belkacem
authors.initials: B
authors.lastname: Abdous
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Camden
authors.forename: Karine
authors.initials: K
authors.lastname: Bouchard
authors.forename: David
authors.initials: D
authors.lastname: Goldgar
authors.forename: Jacques
authors.initials: J
authors.lastname: Simard
authors.forename: Michel
authors.initials: M
authors.lastname: Dorval
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D001943:Breast Neoplasms / Q000235:genetics*; D005192:Family Health; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease / Q000523:psychology*; D005820:Genetic Testing / Q000706:statistics & numerical data*; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000235:genetics*; D012107:Research Design; D013223:Statistics as Topic / Q000379:methods*; D013315:Stress, Psychological; D011795:Surveys and Questionnaires